Cyclospora is an emerging human intestinal pathogen (Ortega, et al., 1993, 1994). Since 1979, oocyst-like structures have been detected in the stool of humans with diarrhea (Ashford, 1979). These structures are spherical, 8-10 .mu.m in diameter, autofluorescent, stain variably with acid-fast techniques, and contain clusters of membrane-bound globules. A variety of workers have referred to this organism as a blue-green alga (cyanobacterium-like body), a fungal spore, a coccidian-like body, and a large cryptosporidium (Long, et al., 1991; Ashford, et al, 1993). In 1993, in vitro sporulation and excystation of these cyanobacterium-like bodies revealed the presence of two sporocysts per oocyst and two sporozoites per sporocyst, leading to re-classification and naming of this organism as a species of the coccidian genus, Cyclospora (Ortega, et al., 1993, 1994).
Increasing numbers of reports suggest that this cyclosporan is an important cause of prolonged diarrheal disease in humans throughout the world (Wurtz, 1994). In one recent study, Cyclospora was found in fecal specimens from 11% of Haitians seropositive for the human immunodeficiency virus who had chronic diarrhea (Pape, et al., 1994). In most of these patients it was the sole pathogen identified and was detected repeatedly. Evidence favoring a role for this organism as a pathogen includes a significant association of oocysts with clinical illness (in absence of other known pathogens), clinical response to antimicrobial therapy, and clearance of organisms coincident with clinical resolution (Page, et al., 1994; Shlim, et al., 1991; Hoge, et al., 1993; Hoge, et al., 1995). Human cyclosporiasis is clinically indistinguishable, however, from cryptosporidiosis, isosporidiosis, giardiasis and microsporidiosis. Epidemiologic data indicate that the human-associated Cyclospora is transmitted by water and by food (Hoge, et al., 1993; Pieniazek, et al., 1996; Centers for Disease Control (CDC), 1996).
Prior to the discoveries disclosed herein, there was no simple way to conclusively diagnose Cyclospora infection in a primate, or to monitor water or food supplies for the presence of Cyclospora.